Re: New MSI support in sata_sil24 still broken in 2.6.33-rc3

[Leon Woestenberg]

Hello Kyle,

I'm also using SIL3234 (sil24 driver) on P2020 and encountering
problems. Instead of starting my own investigation first I used google
powers to find this old email thread.

Have you found a more recent working solution to your problem?

Regards,

Leon.


On Sat, May 29, 2010 at 2:05 AM, Moffett, Kyle D
<Kyle.D.Moffett@xxxxxxxxxx> wrote:
> My advance apologies if this email gets badly MIME-mangled...
>
> On 2010/01/06 20:59, "Robert Hancock" <hancockrwd@xxxxxxxxx> wrote:
>> On 01/06/2010 03:37 AM, Torsten Kaiser wrote:
>>> After activating the MSI support by adding sata_sil24.msi=1 to the
>>> kernel command line, the first write to a drive attached to the SiI
>>> 3132 controller results in the following errors:
>>>
>>> [  138.950074] ata2.00: exception Emask 0x0 SAct 0xf SErr 0x0 action 0x6
>>> frozen
>>> [  138.961023] ata2.00: failed command: WRITE FPDMA QUEUED
>>> [  138.970034] ata2.00: cmd 61/00:00:a5:95:4a/04:00:01:00:00/40 tag 0
>>> ncq 524288 out
>>> [  138.970037]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask
>>> 0x4 (timeout)
>>
>> Looking at the code in sata_sil24 and the SiI3132 datasheet, there's a
>> control bit which doesn't seem to be handled in the driver, global
>> control register bit 30: "MSI Acknowledge (W). Writing a one to this bit
>> acknowledges a Message Signaled Interrupt and permits generation of
>> another MSI. This bit is cleared immediately after the acknowledgement
>> is recognized by the control logic, hence the bit will always be read as
>> a zero. If all interrupt conditions are removed subsequent to an MSI, it
>> is not necessary to assert this Acknowledge; another MSI will be
>> generated when an interrupt condition occurs."
>>
>> The way the interrupt handler for this driver works is that we check the
>> global IRQ status register, and then based on what ports indicated an
>> interrupt in that register, we check the individual port command
>> completion registers. The issue would seem to be that if a port got an
>> interrupt condition in between these two operations, we'd miss it, and
>> the MSI logic described above then wouldn't generate any more interrupts
>> since we didn't remove all interrupt conditions.
>>
>> Can you try this patch and see if it helps? (Might be whitespace damaged
>> but hopefully you can apply manually in that case.)
>
> I've got this custom board that uses the sata_sil24 driver (off a P2020
> processor).  My current kernel is a slightly patched 2.6.32 kernel
> (including the sata_sil24 enable-MSI patch).
>
> Unfortunately when I turn MSI on, I get the exact same hang described here,
> boot log included as dmesg1.txt.
>
> With this patch applied, it seems to get a little further (dmesg2.txt), but
> still dies miserably.
>
> I'm relatively sure that MSI works on this chipset as I also have an e1000e
> controller off an adjacent PCI-E bus which works correctly with MSI.
>
> It's relatively critical for me to get MSI working, because the legacy-PCI
> INTx interrupt for that PCI-E port happens to share an IRQ line with a
> device that is very unfriendly to shared IRQs (it has no internal IRQ
> disable register).  I'd rather not have to go in there with a soldering iron
> and some scraps of wire to make it work. :-D
>
> Cheers,
> Kyle Moffett
>
>



-- 
Leon
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